A fossilized aroid infructescence, Albertarum pueri gen.nov. et sp.nov., of Late Cretaceous (Late Campanian) age from the Horseshoe Canyon Formation of southern Alberta, Canada

Abstract

A fossilized aroid infructescence has been recovered from the Horseshoe Canyon Formation in southern Alberta, Canada. Its stratigraphic position places it near the end of the Campanian Stage of the Late Cretaceous Epoch, at an absolute age of approximately 72 million years before present. It is one of the few Cretaceous aroid fossils known at present, and it represents a new genus of Araceae, here named Albertarum. The infructescence is fertile to the apex, and the flowers must have been bisexual. Flowers bear remains of a long, attenuated style, surrounded by a perigone of six tepals. A fracture reveals ellipsoid seeds with a thick, ribbed testa and traces of a raphe, arranged in groups of three. The gynoecium was probably trilocular with one ovule per locule, and ovules were anatropous, probably with apical–parietal or axile placentation. Bisexual, perigoniate flowers occur in subfamilies Gymnostachydoideae, Orontioideae, Pothoideae, Monsteroideae, and Lasioideae, no genera of which have ribbed seeds, but the infructescence and stylar region of Albertarum resemble those of extant Symplocarpus (Orontioideae). The Horseshoe Canyon Formation was deposited in a delta plain setting, and like Symplocarpus, Albertarum probably grew in a wetland environment.Key words: fossil, Araceae, Symplocarpus, Albertarum, Limnobiophyllum, Mayoa.